This invention relates to generally to the field of preparing food products in tubular casings. The invention relates more specifically to the field of preparing sausages and whole-muscle meats. The invention will be described as used for the production of sausages, but it applies equally to the production of whole-muscle meats, cheeses, vegetarian food products, and any other material that is wrapped in a casing.
Sausages are conventionally produced by extruding a pasty mixture of meat products, spices, and fillers into a tubular casing. (Some sausages are then wrapped in netting prior to processing.) The casing comes in several forms. Edible collagen films, for example, including flavored and colored films, remain on the sausage after processing. Inedible films are used solely for packing the sausage and are removed prior to use.
There are two types of casings conventionally used: tubular casings and flat sheets. Tubular casings are shirred onto a horn that is then placed over the discharge of the sausage stuffer/clipper. Illustrative processes and devices for making sausage from tubular casings are described in, for example, U.S. Pat. No. 5,024,041 to Urban, Process for Filling Tubular Casings and in U.S. Pat. No. 7,063,610 to Mysker, Apparatus and Method to Net Food Products in Shirred Tubular Casing, the disclosures of which are both incorporated herein by reference. This method has the advantage of not having a seam in the casing. However, the casing must first be shirred over a horn before use, which adds a step in the manufacturing process. Additionally, once the shirred casing on the horn runs out, the sausage-making process must be stopped to remove the empty horn and to either re-shir the horn with fresh casing or to attach a spare horn on which casing has already been shirred.
In another method, flat sheets of film, such as collagen film, are turned over plows by an automatic heat-sealing machine to produce a tubular casing. A representative process is shown in, for example, U.S. Pat. No. 4,985,477 to Winkler, Apparatus for Production of Meat Products. The use of flat sheets eliminates the need to shir the casing onto a horn prior to use and allows for extended use. But some films cannot be heat sealed and accordingly are not well-adapted to this method. Additionally, this method leaves a seam in the casing, which can be undesirable.
A sausage maker using one of these methods may need to switch to the other method because of production needs caused by customer demands. Switching a sausage-making line from one method to the other causes an interruption in the manufacturing process. A conventional sausage stuffer/clipper can operate continuously for a long period of time. But every time the sausage maker wants to switch from one type of casing to the other, the manufacturing process must be stopped to change the equipment. A solution to this problem was addressed in U.S. Pat. No. 7,306,511 to Whittlesey et al., Systems with Interchangeable Horns for Producing Encased Products and Related Methods, Computer Program Products and Horn Rotor Assemblies. Another solution was proposed in U.S. Pat. No. 7,544,118 to Mysker et al., Hybrid Filling System. The present invention improves on these solutions by simplifying the horn arrangement and thereby minimizing the downtime caused by switching from one type of casing to another.